1. Field of the Invention
The present invention generally relates to evaluation methods of probe marks (contact marks or needle traces) of probe needles of probe cards, and more specifically, to an evaluation method of a probe mark (contact mark or needle trace) of a probe needle of a probe card used for inspecting an electrical property of a semiconductor element provided on a wafer.
2. Description of the Related Art
Conventionally, in a product manufacturing process of a semiconductor device, an integrated circuit (hereinafter “IC”) mounted on a wafer has been connected to a tester and a function test for operating a circuit is implemented, so that a bad IC element is found at an early stage and thereby manufacturing cost of the semiconductor device is reduced and productivity of the semiconductor device is improved.
In such a function test, a probe card is used as an IC inspection card in order to wire from the tester to the electrode pad provided on the IC for a while. In the probe card, a probe needle is arranged in advance so as to correspond to an arrangement of the electrode pad of the IC which IC is an object of the inspection.
More specifically, the probe needle of the probe card is made to come in contact with the electrode pad of the IC being the object of the inspection by a driving apparatus called a prober so that a probing test, namely inspection of the electrical property of the IC, is implemented.
In the meantime, as the semiconductor devices have become minute recently, the pitch between the electrode pads and the size of the electrode pads have become narrower. As corresponding to this, a probing technique at high precision has been in demand. Especially, high precision is required for positioning the prober and positioning the probe needle of the probe card.
In addition, Japanese Laid-Open Patent Application Publication No. 2-137347 discloses an inspection method. In this method, a reference data element at the time of positioning a probing needle is prepared through a learning operation. When new species are used as a semiconductor wafer and a probing card corresponding to the wafer, the learning operation is executed using information previously provided by an instruction manual for the first time, stored as positioning information (a reference data element), and information for the second and subsequent positioning of an electrode pad and the probing needle is read from the memory and automated. That is, the reference data element is stored together with a probing-card code, thus automatically conducting subsequent learning.
Furthermore, Japanese Laid-Open Patent Application Publication No. 2005-123293 discloses a method for an inspection probe. In this method, the probe card is set. A probe mark confirming member arranged in a region for confirming a probe mark formed on a needle-point grinding machine and the needle point of a probe needle for the probe card are aligned. The probe needle is brought into contact with the probe mark confirming member, and the probe mark is formed. The location of the probe mark is detected by a first camera, and the displacement of the location of the detection and the target location of the probe mark to be formed on the probe mark confirming member is obtained. The semiconductor wafer to be inspected is placed on a stage, and the chip of the semiconductor wafer and the needle point of the probe needle are aligned. An electrode pad for the chip is brought into contact with the probe needle but the displacement previously obtained is used in the case of the contact, and the location of the contact is corrected.
However, in the above-discussed related art technique, after a test wafer or a product wafer manufactured as a product is first manufactured, the probe needle of the probe card is made to come in contact with the electrode part of such a product wafer and then the probe mark is checked so that whether the probe needle is within the electrode pad is determined.
Therefore, in a case where the probing test is implemented for the product wafer, if the arrangement of the electrode pad is newly designed, high cost is incurred for the inspection. In addition, if a bad situation exists in the product wafer, the probing test cannot be implemented at that time and this causes delay of product delivery to a customer.
On the other hand, in a probing test when there is no product wafer, the positioning precision of the probe needle is checked by using the probe card inspection device, or a wafer of which the entire main surface is made of aluminum is used and the probe mark of the probe needle formed in the wafer is checked by eye. However, these checks are not sufficient for the inspection, and therefore confirmation using the product wafer is eventually required.